In chemical and other kinds of industrial processing plants, plastic pipe is commonly suspended from overhead structures, such as horizontal I beams supported by columns. One conventional method for suspending plastic pipe from an I beam has been to weld a horizontal angle iron extension to the beam, and attach a vertical hanger rod to the extension, which rod supported a clevis-type hanger through which plastic pipe was inserted. A wear plate was placed between a lower surface of the plastic pipe and the clevis to prevent excessive wear to the surface of the pipe. Compared to metal pipe, a run of plastic pipe requires supports at more frequent intervals in order to avoid excessive droop. For example, the recommended hanger spacing for a one-inch diameter carbon steel Schedule 40 pipe carrying water at 140 degrees F. is seven feet, compared to every 3.2 feet for the same fluid carried in a PVC Schedule 40 one-inch diameter pipe. See: Franklund, Thomas W., Pipe Fitters and Welders Handbook (Glencoe Publishing Co., Encino, Calif., 1984). Therefore, a greater number of such hangers distributed along a run of plastic pipe has been necessary to provide adequate support for a run of plastic pipe compared to a run of metal pipe.
The present invention, by providing a saddle hanger having a longitudinally extended, U-Shaped pipe support surface, significantly reduces the number of hangers required for a given run of plastic pipe, while at the same time minimizing the droop. With increased supporting surface, a wear plate is no longer required.
Kindorf, U.S. Pat. No. 3,415,474, described a hanger for insulated pipe comprising a U-shaped hanger strap supported by a clevis suspended by a threaded rod from an overhead structure. Richards, U.S. Pat. No. 5,007,604, disclosed a side load type pipe hanger comprising a generally C-shaped saddle including a pair of spaced apart arm portions and an interconnecting bight portion, and a support leg member connected to the saddle for suspending the hanger from an overhead structure. Neither Kindorf nor Richards, however, addressed the problem of droop in a run of plastic pipe, and neither taught the use of a longitudinally extended hanger strap to minimize droop.
Other pipe hanger systems known in the patent literature for suspending pipe from an I beam are disclosed by the following U.S. Pat. Nos. 1,737,214, granted Nov. 26, 1929, to S. Brown; U.S. Pat. No. 3,572,623, granted Mar. 30, 1971, to Chester A. Lapp; U.S. Pat. No. 4,019,705, granted Apr. 26, 1977, to Blair A. Habuda, Sr. et al.; and U.S. Pat. No. 4,570,885, granted Feb. 18, 1986, to Richard W. Heath. Again, however, none of these references teaches apparatus to minimize droop in a run of plastic pipe.